This invention relates in general to vehicle emergency warning systems, and more particularly to an electronic deceleration/accident warning system for a motor vehicle having a high energy strobe light facing following traffic, and a microcontroller for controlling the strobe light flash pattern and other safety devices, in response to different emergency situations, such as rapid deceleration, collision, accident while parked, among others.
Inertial activated devices are well known for turning on a warning signal at the rear of an automobile.
U.S. Pat. No. 3,286,055 (Jewell) discloses an impact switch for a motor vehicle for enabling a flashing warning light in the event of impact. The device comprises an impact switch, flasher and a dry cell battery which are all housed in a self-contained unit, which is separable from the vehicle. A breakable rod is inserted vertically into a movably weight so as to hold the switch in an open position. On impact, the weight moves, breaks the rod and closes the switch to enable the flashing warning light.
U.S. Pat. No. 3,762,495 (Usui et al) discloses a method and device for generating and transmitting a signal to a vehicle safety device (such as an air bag or net) in response to rapid deceleration of the vehicle. A signal voltage corresponding to the magnitude of deceleration is generated by a detector and compared via a comparator to predetermined deceleration values (i.e. pre-set voltages) which correspond to different levels of deceleration, and different rates of change in deceleration. When the deceleration is within predetermined ranges, a signal is generated to trigger the safety device. A variety of preset levels are provided corresponding to different types of impact (e.g. car against barrier, side-car collisions, etc.).
U.S. Pat. No. 4,176,340 (Steinmeier) discloses an apparatus for automatically activating a flasher system in response to a vehicle shock, such as occurs with hard braking or an accident. The system can be connected to vehicle flashers or turn signals. The system consists of an upright cylinder housing with an internal switch. An iron plate is also provided inside the housing along with a tiltable magnetic element that tilts on the application of a shock. The tilt of the magnetic element pulls a trip wire that closes the switch for activating the flashers. To reset the device, the flashers must be manually turned on, and then off.
U.S. Pat. No. 4,384,269 (Carlson) discloses a vehicle acceleration and deceleration warning system where the visual indicators of acceleration and deceleration also serve as turn signals. The warning system has priority over the turn signals. An electromechanical transducer converts deceleration into an electrical quantity which changes according to the rate of deceleration. The transducer consists of a pendulum that swings forward and backward (based on acceleration and deceleration) into the path of a light and invariably blocks the light from reaching a set of optical sensors. The optical sensors generate a variable voltage signal based upon the amount of light striking them. The variable signal activates a variable oscillator that causes the signal lights to flash at a rate which is proportional to the rate of deceleration. If the deceleration rate is above a predetermined threshold, the signal lights remain flashing until they are manually reset.
U.S. Pat. No. 4,470,036 (Doerr) discloses an automotive signal system consisting of three modes: stop, caution and go with three corresponding coloured lights. The ignition switch is used to turn on the signal. In one embodiment, the stop light is triggered by the brake pedal, the caution light is triggered by a release of the gas pedal, and the green light is triggered by depressing the gas pedal. In an alternative embodiment, the lights are triggered by the acceleration and deceleration of the vehicle detected via a mass suspended inside a chamber between two springs. When the vehicle decelerates, the mass moves forward, triggering the stop light. When the vehicle accelerates, the mass moves backwards, triggering the green light. When the mass is stationary, the caution light is lit.
U.S. Pat. No. 4,723,078 (Neuffer et al) discloses a circuit arrangement for the automatic engagement of a vehicle hazard warning system, which is triggered by accident and by emergency braking. The system consists of two circuits: one based upon high deceleration of the vehicle (such as in an accident) which automatically engages the hazard warning system; and a second, more sensitive circuit for lower deceleration that engages after a time delay and only in the event of sustained deceleration. The second circuit is also connected to the brake pedal so that hard deceleration does not trigger the flashers. Thus, this prior art system is designed to prevent false activation which may be caused by bumps or curves.
Japanese laid-open specification number 0047232 (Orihashi) discloses a device for activating a lamp in response to rapid deceleration. The device consists of a movable weight inside a cylinder. When the vehicle slows down, the weight moves and closes the switch for turning on the light.
Accordingly, prior art warning systems are known for initiating flashing of a light for notifying any following traffic of an emergency, wherein the frequency of the light is determined by the amount of detected g-forces of deceleration. Furthermore, it is known from the prior art to activate different safety devices in response to detecting multiple g-forces of deceleration (e.g. U.S. Pat. No. 3,762,495). However, such prior art systems have typically been realized using mechanical or electromechanical g-force sensors for controlling the warning light or safety device. Mechanical sensors are known to be unreliable and prone to breakage. Similarly, discrete electrical components are subject to failure and inaccuracy due to voltage drift, etc. Furthermore, such prior art devices typically provide one or more predefined operating modes, without the ability to provide multiple operating modes with definable primary and secondary functions.
In particular, the Applicants are unaware of any teaching in the prior art of a vehicle emergency warning system in which a high energy strobe light is used to warn following traffic of an emergency situation, and in which a microcontroller and g-level sensor are incorporated for effecting two primary functions: firstly, causing the strobe light to flash according to a first predetermined pattern in the event of hard deceleration of the vehicle, and secondly causing the strobe light to flash according to a second predetermined pattern which is perceptively different from said first predetermined pattern in the event of a collision, in combination with one or more secondary functions which may include causing the strobe light to flash according to the aforementioned second predetermined pattern in the event that the ignition is off and the car is bumped or rocked while parked, or causing the strobe light to flash according to the aforementioned second predetermined pattern in response to the microcontroller receiving an input signal from an existing theft alarm system installed on the vehicle, or controlling activation of various existing safety systems such as safety belt tensioners and airbags in response to high deceleration or collision. The frequency of flashing the strobe light is preferably more than twice the normal flashing frequencies of any other lamps operating on the vehicle (e.g. turn indicator, hazard warning, etc.), in order to distinguish a real emergency situation from normal vehicle signalling.
According to the present invention, a microcontroller-based vehicle emergency warning system is provided comprising a high energy, flashing strobe light which is disposed in the vehicle so as to face following traffic and a microcontroller-based system for providing two primary functions and a plurality of secondary functions. The first primary function is that of providing a warning signal to the following traffic in the form of a first predetermined pattern which, according to the preferred embodiment, comprises continuous high-frequency, high energy flashes in the event of sudden application of the brakes and high levels of deceleration. The second primary function is that of providing a warning signal to the following traffic in the form of a second predetermined pattern which, according to the preferred embodiment, comprises intermittent high frequency, high energy flashes in the event of vehicle impact. The first secondary function of the system is that of providing the second predetermined pattern of high energy flashes of the strobe light in the event the vehicle is hit while parked. The second secondary function is that of providing the second predetermined pattern of high energy flashes of the strobe light upon receiving an input signal from an existing theft alarm signal. The third secondary function is that of monitoring an input from an existing ABS system and overriding the requirement of detecting high rate of deceleration before executing the aforementioned first primary function in the event of activation of the ABS system, which is useful in driving conditions which are conducive to vehicle skidding such as on an icy or wet roadway. According to an additional aspect of the invention, further active safety devices such as safety belt tensioners and air bags may be controlled in response to one or both of high levels of deceleration and impact.
The system of the present invention includes a backup power supply which is activated only in the event of an accident in which the vehicle battery has been destroyed. Thus, according to this feature of the invention, the system remains in operation to perform the second primary function even in the case of serious collision.
By implementing the vehicle emergency warning system of the present invention utilizing a microcontroller, greater flexibility and reliability are provided over prior art systems of which the applicants are aware. Furthermore, the control unit of the present invention may be fabricated at low cost and with minimal space requirements in the vehicle.